Round stop device for a machine gun feeding mechanism



ROUND STOP DEVICE FOR A MACHINE GUN PENDING MECHANISM S O T N A S A. E

2 Sheets-Sheet 2 Filed March 2, 1966 ATTORNEY 3 340,770 ROUND S'IP DEVICE FR A MACHINE GUN FEEDING MECHANISM Edward A. Santos, Thompsonville, Conn., assignor to the United States of America as represented by the Secretary of the Army Filed Mar. 2, 1966, Ser. No. 533,129 3 Claims. (Cl. 89--33) ABSTRACT F THE DISCLOSURE ment by the rearwardly moving barrel. Cooperating cam means on the round stops and barrel pivot the round stops to open positions clear of the barrel and the ejection port when the barrel moves rearwardly to its tiring position and to their stopping positions when the barrel is moving forwardly to its loading position. Plungers actuatable by the barrel are located in the round stops and are arranged to releasably hold the round stops in their open and stopping positions.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

In machine guns of known type, the barrel is reciprocated between a forward cartridge loading position and a rearward ring position and the cartridges are successively moved radially downward into the receiver for engulfment by the barrel when traveling from the loading to the ring position. The tired case is held back when the barrel moves forwardly after iiring, for extraction therefrom, by an extractor and when the rear end of the barrel is clear of the ired case the case is ejected downwardly by an ejector through a port in the bottom of the receiver.

This raises problems as to the feeding of the cartridges into the receiver as some means must be provided for controlling the incoming cartridge so that it will not continue its downward travel through the ejection port. There must also be provided some means for holding the cartridge in alignment with the barrel ready for engulfment thereby. These means, however, must not interfere with the rearward travel of the barrel and must not block the ejection port to prevent ejection of the red case therethrough after the barrel has passed thereby during its forward travel after firing.

These problems have been overcome by the present invention which provides a pair of pivotal round stops which stop the incoming cartridge in alignment with the barrel and which cooperate with the feed pawl that moves the cartridge into the receiver to hold the cartridge for engulfment by the barrel. The round stops are cammingly pivoted out of the way to their open positions by the barrel after the front portion of the cartridge has entered the chamber of the rearwardly traveling barrel and the stops are releasably held in the open positions clear of the ejection port after the barrel has moved forwardly clear of the tired case, a period of time sucient for the ejection thereof. The stops are released to be cammingly returned to their stopping positions by the barrel before it reaches its loading position.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from 3,340,770 Patented Sept. 12, 1967 a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. 1 is an elevational view of the receiver and cam drum section of a machine gun of the aforementioned type with the barrel located in its forward loading position;

FIG. 2 is a View taken along line 2-2 of FIG. l;

FIG. 3 is a view similar to FIG. 2 but shows the round stops located in their open positions for ejection of the red case therethrough;

FIG. 4 is a view taken along line 4 4 of FIG. 2 and shows one of the two round stops held in its stopping position;

FIG. 5 is `a fragmentary view similar to FIG. 4 but shows the relationships of the round stop and cooperating parts when the front portion of the cartridge is received by the barrel chamber during rearward travel thereof; and

FIG. 6 is a view similar to FIG. 4 but shows the relationship of the parts when the barrel is in its tiring position with the cartridge chambered and moved back to its battery position.

Shown in the figures is a machine gun 12 having a receiver 14 and a barrel 16 which is reciprocated between a forward cartridge loading position and a rearward firing position. A feeding mechanism 18 includes a pawl 20 which is arranged for vertical reciprocation to successively feed cartridges 22 to a feeding position in receiver 14 and which is extendable into the receiver to maintain contact with the cartridge after being moved thereby to the feeding position. Receiver 14 includes a mouth 24 through which cartridge 22 is transferred downwardly into the receiver and an ejection port 26 in the bottom of the receiver for ejection of red case 28 therefrom.

Cartridge 22, when fed into receiver 14 by pawl 20, is stopped in the feeding position, which is slightly forward of battery position and over ejection port 26, by a pair of round stops 40. As shown in FIG. 2 and as described hereinafter, cartridge 22, when in the feeding position, is held in alignment with barrel 16 through the cooperation of pawl 20 with round stops 40 which secure the cartridge by three point contact.

Each of the round stops 40 is mounted in a channel 42 provided therefor in receiver 14 and the channels are symmetrically disposed apart on opposite sides of ejection port 26. The round stops 40 are each pivotally mounted between the front and rear ends thereof on a pin 44 so as to be movable between an open and a stopping position in a radial path respective to the long axis of barrel 16. Each of the channels 42 is formed in receiver 14 Ifrom the outside thereof. A front orifice 46 provides communication between the front end of each of the channels 42 and the inside of receiver 14 and a rear onice 48 provides communication between the rear end of each of the channels and the inside of the receiver.

Round stops 40 are each provided at the rear end with an integral tongue 50 which is received by the corresponding rear orifice 48. As is especially well shown in FIGS. 4-6, tongues 50- extend into receiver 14, vwhen round stops `40 are in their stopping positions, to cooperate in blocking ejection port 26 and stopping cartridge 22 fed into receiver 14 by pawl 20 in the feeding position. When round stops 40 are in their open positions, as shown in FIG. 3, tongues 50 are retracted within the related rear orilices 48 out of interference with barrel 16 and clear of ejection port 26 which is thereby unblocked for passage of red case` 28 therethrough.

Each of the round stops 40 is releasably retained in its stopping position by a spring-'biased plunger 52 which is mounted in a mating well S4 that extends rearwardly from an inclined front face 56 of the related tongue 50 so as to be forwardly extendable therefrom over the adjacent inside surface '5 of receiver 14, as shown in FIG. 4. When barre-l 16 partially envelops cartridge 22, during rearward travel to the firing position, the rear end of the barrel, as shown in FIG. 5, contacts the ends of plungers 52 and continued rearward travel of the barrel presses the plungers rearwardly until the ends thereof are in registry with rear orifices 48, and clear of inside surface 55 of receiver 14, for release of round stops `40. During final rearward travel o-f barrel 16 to the ring position, the end of the barrel contacts front faces 56 of tongues 50, which are inclined so that round stops 40 are cammingly displaced to their open positions out of interference with the rearwardly moving barrel. Also, the final movement of barrel 16 to the firing position moves cartridge 22 from its feeding position to battery position against a pair of extractors 68 (only one of which is shown) which snap over the rim of the cartridge case to engage extractor groove 70 therein when the 'barrel reaches the iiring position.

Provided on the front end of each of the round stops 40 is a ange 60 which extends upwardly so as to lbe received by the related front orifice 46. Mounted in flange 60 is a spring-biased plunger 62 which is pressed rearwardly from a mounting `hole 63 extending forwardly into the flange from an inclined rear face 66 thereof. Plungers 62 are extendable over the adjacent inside surface 55 of receiver 114 when the round stops 40 are in their open positions for releasably locking the round stops therein, as shown in FIG. 6.

The ends of plungers 62 are contactable by a forwardly facing shoulder 64 on barrel 16 when the barrel is adjacent the loading position so that during the continued forward travel of the barrel thereto the ends of the plungers are pressed into registry with front orifices 46 and clear of inside surface 55 of receiver 14 for release of round stops 40. After the ends of plungers 62 are clear of inside surface 55, shoulder 64 contacts the inclined rear faces 66 of anges 60 so that barrel 16 during its continued final travel to the loading position cams round stops 40 to their stopping positions. When barrel 16 is in its loading position, flanges 60 contact the 'barrel rearwardly of shoulder 64, as shown in FIG. 4, so that the impact of cartridge 22 against tongues 50, when transferred to the feeding position, is borne by the barrel.

Operation The operation of machine gun 12 is designed so that when barrel 16 is adjacent the loading position a cartridge 22 is transferred by pawl 20 to the feeding position in receiver 14. At this time round stops `40 are latched in their stopping positions and are supported by the barrel ready to receive cartridge 22 and assist pawl 20 in holding t-he cartridge in alignment with barrel 16. As the movement of barrel 16 proceeds rearwardly to the firing position and the front of cartridge 22 is received by the barrel, the rear end of the barrel presses plungers '52 rearwardly to unlatch round stops 40 and then contacts front faces '56 to cam the round stops to their open positions out of interference with the continued rearward movement of the barrel.

When the round stops 40 are pivoted to their open positions, plungers 62 snap from front orifices 46 rearwardly over inside surface 55 of receiver 14 to releasably latch the round stops in their operi positions. As barrel 16 moves to the firing position, cartridge 22 is moved rearwardly therewith from its feeding position to the battery position with extractors 68 snapping over the rim of the cartridge case into engagement with extractor groove 70.

When cartridge 22 is fired and barrel 16 moves forwardly to the loading position, fired case 28 is held stationary by the extractors 68 for extraction from the barrel. When the rear end of barrel 16 is clear of fired case 28, it is ejected by an ejector mechanism not shown Ibetween round stops `40 and out ejection port 26. As barrel 16 approaches the loading position, shoulder 64 thereon -contacts plungers 62, to unlatch round stops 40 from their open positions, and then contacts rear faces 66 to cam the round stops to their stopping positions ready to cooperate with pawl 20 in receiving the next cartridge fed thereby into receiver 14. When round stops 40 reach the stopping positions, plungers `52 snap over inside surface 55 to releasably latch the round stop therein.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be ydevised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. 'In a machine gun having a receiver with an ejection port in the underside thereof, a barrel mounted in the receiver for reciprocation between a forward loading position and a rearward firing position, a pawl for feeding a cartridge radially to a feeding position in the receiver over the ejection port and in coaxial alignment with said barrel for engulfment thereby during travel to the firing position, a pair of round stops pivotally mounted on the receiver for radial displacement respective to said barrel between open positions clear of the ejection port and stopping positions extending into the receiver for cooperation with said pawl to hold the cartridge in the feeding position, a pair of channels formed in the receiver from the outside thereof for receiving said round stops, pin means for pivotally mounting said round stops between the front and rear ends thereof, a tongue extending from the rear end of each of said round stops through a rear orifice communicating with the inside of the receiver to provide contact of said tongue with the cartridge when in the feeding position, a fiange extending from the front end of each of said round stops through a front orifice communicating with the inside of the receiver to provide contact of said flange wit-h said barrel when in the loading position for blocking displacement of said round stops from their stopping positions, a rst latching means for releasably holding said round stops in the stopping positions, and a second latching means for releasably holding said round stops in the open positions.

2. The machine gun as defined in claim 1 wherein said first latching means includes a spring-biased plunger mounted in each of said tongues for forward extension over an inside surface of the receiver when the respective one of said round stops is in the stopping position to block displacement therefrom, and said second latching means includes a spring-biased plunger mounted in each of said flanges for rearward extension over the inside surface of the receiver when the respective one of said round stops is in the open position, said plungers of said first latching means, being contactable iby the rear end of said ibarrel during travel to the tiring position for displacing said plungers in said tongues clear of the inside surface to release said round stops for displacement from the stopping positions, and said plungers of said second latching means being contactable by a shoulder on said barrel during travel thereof to the loading position for displacing said plungers in said flanges clear of said inside surface to release said round stops for displacement from the open positions.

3. The machine gun as defined in claim 2 wherein said tongues are each provided with an inclined front face contactable by the rear end of said barrel after release of said round stops from the stopping positions to cammingly actuate said round stops to the operi positions during final displacement of said barrel to the firing position, and wherein said anges are each provided with an inclined rear face contactable by said shoulder after release of said round stops from the open positions to cammingly actuate said round stops Y 5 6 to the stopping positions during final displacement of 2,557,144 6/ 1951 Schaich 89-33 X said barrel to the loading position. 2,790,355 4/ 1957 Sanford 89-33 References Cited SAMUEL FEINBERG, Primary Examiner. UNITED STATES PATENTS 5 BENJAMIN A. BORCHELT, Examiner. 150,102 4/1874 Swingle et a1 42-11 s. C. BENTLEY, Assistant Examinar. 715,971 12/1902 Burgess 89-161 X 

1. IN A MACHINE GUN HAVING A RECEIVER WITH AN EJECTION PORT IN THE UNDERSIDE THEREOF, A BARREL MOUNTED IN THE RECEIVER FOR RECIPROCATION BETWEEN A FORWARD LOADING POSITION AND A REARWARD FIRING POSITION, A PAWL FOR FEEDING A CARTRIDGE RADIALLY TO A FEEDING POSITION IN THE RECEIVER OVER THE EJECTION PORT AND IN COAXIAL ALIGNMENT WITH SAID BARREL FOR ENGULFMENT THEREBY DURING TRAVEL TO THE FIRING POSITION, A PAIR OF ROUND STOPS PIVOTALLY MOUNTED TO THE RECEIVER FOR RADIAL DISPLACEMENT RESPECTIVE TO SAID BARREL BETWEEN OPEN POSITIONS CLEAR OF THE EJECTION PORT AND STOPPING POSITIONS EXTENDING INTO THE RECEIVER FOR COOPERATION WITH SAID PAWL TO HOLD THE CARTRIDGE IN THE FEEDING POSITION, A PAIR OF CHANNELS FORMED IN THE RECEIVER FROM THE OUTSIDE THEREOF FOR RECEIVING SAID ROUND STOPS, PIN MEANS FOR PIVOTALLY MOUNTING SAID ROUND STOPS BETWEEN THE FRONT AND REAR ENDS THEREOF, A TONGUE EXTENDING FROM THE REAR END OF EACH OF SAID ROUND STOPS THROUGH A REAR ORIFICE COMMUNICATING WITH THE INSIDE OF THE RECEIVER TO PROVIDE CONTACT OF SAID TONGUE WITH THE CARTRIDGE WHEN IN THE FEEDING POSITION, A FLANGE EXTENDING FROM THE FRONT END OF EACH OF SAID ROUNDS STOPS THROUGH A FRONT ORIFICE COMMUNICATING WITH THE INSIDE OF THE RECEIVER TO PROVIDE CONTACT OF SAID FLANGE WITH SAID BARREL WHEN IN THE LOADING POSITION FOR BLOCKING DISPLACEMENT OF SAID ROUND STOPS FROM THEIR STOPPING POSITIONS, A FIRST LATCHING MEANS FOR RELEASABLY HOLDING SAID ROUND STOPS IN THE STOPPING POSITIONS, AND A SECOND LATCHING MEANS FOR RELEASABLY HOLDING SAID ROUND STOPS IN THE OPEN POSITION. 